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| United States Patent |
5,354,915
|
|
Reichle
|
October 11, 1994
|
Catalysts for the reduction of carbonylic compounds to alcohols
Abstract
This invention provides an improved process for converting
.alpha.,.beta.-olefinically unsaturated aldehydic or ketonic compounds
into the corresponding allylic alcohol using an alcohol as a hydrogen
donor. This process is conducted in the presence of a supported tetragonal
zirconium oxide catalyst or supported HfO.sub.2, V.sub.2 O.sub.5,
NbO.sub.5, TiO.sub.2 and Ta.sub.2 O.sub.5 catalysts.
| Inventors:
|
Reichle; Walter T. (Warren, NJ)
|
| Assignee:
|
Union Carbide Chemicals & Plastics Technology Corporation (Danbury, CT)
|
| Appl. No.:
|
994630 |
| Filed:
|
December 21, 1992 |
| Current U.S. Class: |
568/881; 502/242; 568/347; 568/374; 568/391; 568/433; 568/465; 568/813; 568/820 |
| Intern'l Class: |
C07C 027/00; C07C 029/14; C07C 029/143; C07C 033/03 |
| Field of Search: |
568/881,813,820
|
References Cited
U.S. Patent Documents
| 2507647 | May., 1950 | Robeson et al. | 568/881.
|
| 2767221 | Oct., 1956 | Ballard et al. | 568/881.
|
| 3551497 | Dec., 1970 | Wymore | 568/881.
|
| 4731488 | Mar., 1988 | Shimasaki et al. | 568/814.
|
| 4847424 | Jul., 1989 | Matsushita et al. | 568/484.
|
Other References
"Acrolein" 1962 edited by Smith, p. 234.
Shibagaki et al., "Catalytic Activity of Hydrous Zirconium Oxide Calcined
at Several Temperatures," Bull. Chem. Soc. Jpn, 63, 258-259 (1990).
Shibagaki et al., "Catalytic Reduction of Aldehydes and Ketones with
2-Propanol Over Hydrous Zirconium Oxide," Bull. Chem. Soc. Jpn, 61,
3283-3288 (1988).
Shibagaki et al., "Vapor-Phase Reuction of Aldehydes and Ketones with
2-Propanol Over Hydrous Zirconium Oxide," Chemistry Letters, pp. 1633-1636
(1988).
Kuznetsov et al., "XPS Study of the Nitrides, Oxides and Oxyntrides of
Titanium," Journal of Electron Spectroscopy and Related Phenomena,
58(1992) 1-9.
Franklin et al., "Stabilisation and Catalytic Properties of High Surface
Area Zirconia," Catalysis Today, 10 (1991) 405-407.
Axelsson et al., "Surface Compositional Changes of ZrO.sub.2 in H.sub.2 O,
H.sub.2 and Atomic Hydrogen, Investigated by AES and EELS," Applied
Surface Science 25 (1986) 217-230.
Morinaga et al., "Electronic Structure and Phase Stability of ZrO.sub.2 ",
J. Phys. Chem. Solids 44 (No. 4) 1983, pp. 301-306.
Kawai et al., "Surface Electronic Structure of Binary Metal Oxide Catalyst
ZrO.sub.2 /SiO.sub.2, " Surface Science III (1981) L716-L720.
Tsuda et al., "Positron Annihilation in ZrO.sub.2 ; Angular Correlation,"
J. Phys. Soc. Jpn. 36 (No. 2) Feb, 74 523-525.
|
Primary Examiner: Evans; Joseph E.
Claims
What is claimed is:
1. In a process for converting an .alpha.,.beta.-olefinically unsaturated
aldehydic or ketonic compound into the corresponding allylic alcohol
derivative which comprises reacting the .alpha.,.beta.-olefinically
unsaturated aldehydic or ketonic compound with an alcohol in the presence
of a metal oxide catalyst supported on a support;
the improvement wherein;
(a) the catalyst is ZrO.sub.2
(b) the support is silica; and
(c) the reaction is conducted in a liquid phase.
2. The process of claim 1 wherein the .alpha.,.beta.-olefinically
unsaturated aldehydic compound is acrolein and the acrolein is reacted
with a secondary alcohol to form allyl alcohol.
3. The process of claim 2 which is performed under substantially anhydrous
conditions.
4. The process of claim 2 wherein a free radical inhibitor is employed in
an amount ranging from 10 about to about 2000 parts per million based on
the weight of acrolein.
5. The process of claim 1 wherein the used catalyst is reactivated by an
oxygen-containing gas at a temperature in excess of 200.degree. C.
Description
FIELD OF THE INVENTION
The present invention relates to supported catalysts useful in organic
reactions. More particularly, the present invention relates to catalysts
comprising at least one metal catalyst supported on a carrier having
utility in processes in which a ketone or aldehyde is converted to the
respective alcohol or an alcohol is oxidized to an aldehyde or ketone.
PRIOR ART
Catalysts are generally classified according to the phase relationship
between the catalyst and the reagents. A heterogeneous catalyst is in a
different phase, i.e., gaseous, liquid, or solid as compared to the phase
of the reagents. Heterogeneous catalysts have the advantage of being
easily removed from a reaction, by techniques such as filtration. The
recovery of the catalyst result in the reuse of the catalyst in the
reaction and a significant cost savings. Heterogeneous catalysts can also
be physically fixed in a reactor which eliminates the need to separate the
catalyst from the reaction product downstream. Disadvantages of the fixed
location catalysts include lower catalytic activity due to agglomeration
of the catalyst or fouling of the catalyst by reaction products. In
addition to the above considerations, the selection of a catalyst for a
particular reaction must provide the desired product(s) at higher
efficiency, while being cost effective.
Several methods are known in the prior art for converting
.alpha.,.beta.-olefinically unsaturated carboxylic compounds into the
corresponding .alpha.,.beta.-olefinically unsaturated alcohols, and
various catalysts are disclosed for improved conversion and yields.
British Patent No. 734,247 and U.S. Pat. No. 2,763,696 disclose a process
whereby acrolein may be converted to allyl alcohol by means of a vapor
phase hydrogenation process. According to this process, moderate yields of
allyl alcohol are obtained when acrolein is treated with free hydrogen in
the vapor phase at a temperature between 210.degree. C. and 240.degree. C.
in the presence of a catalyst comprising cadmium and one or more heavy
metals of groups I, II, VI and VIII of the periodic table. Pressures on
the order of 20 to 50 kilograms per square centimeter are employed in the
process.
German Patent No. 858,247 discloses a somewhat different process which is
also useful for the conversion of acrolein to allyl alcohol. According to
the German patent, allyl alcohol is obtained by reacting acrolein with
free hydrogen in the presence of a catalyst containing cadmium oxide and a
metal hydrogenating component, preferably copper. The patent discloses
that the best results are obtained when the process is operated at high
temperatures and at high pressures on the order of 100-300 atmospheres.
It is known to convert .alpha.,.beta.-unsaturated aldehydes into the
corresponding unsaturated alcohols in the liquid phase by means of
hydrogenation in the presence of a mixture of a copper salt and cadmium.
It is assumed by the patentees that the copper salt is the catalyst and
that the cadmium salt only serves the function of preventing the copper
salt from being reduced to metallic copper. The use of a solution of a
mixture of a copper salt and cadmium salt for catalyst has the
disadvantage that the system is extremely unstable under the required
processing conditions, and fluctuations in conditions can cause reduction
of the Cd.sup.+2 salt and/or the Cu.sup.+2 salt to metals.
U.S. Pat. No. 3,686,333 describes a liquid phase hydrogenation process for
converting alkenals into alkenols in the presence of a catalyst mixture of
a cadmium salt of a fatty acid and a transition metal salt of a fatty
acid.
Japanese Patent No. 73-01,361 discloses a process for hydrogenating
.alpha.,.beta.-olefinically unsaturated aldehydes into the corresponding
allylic alcohol derivatives. The efficiency of the process is improved by
the recycle of by-products to the hydrogenation zone, or by passage of the
by-products stream into a second hydrogenation zone. The preferred
catalysts are mixtures of cadmium and copper, cadmium and silver, cadmium
and zinc, cadmium and chromium, copper and chromium, and the like. The
Japanese patent discloses that under steady state conditions 1.5
moles/hour of acrolein are converted to 1.05 moles/hour of allyl alcohol
and 0.4 mole/hour of n-propanol.
Shibageki et al. discloses the reduction of aldehydes with 2-propanol by
catalysis with hydrous zirconium oxide (100% unsupported) to give the
corresponding alcohol. See for example, Bull. Chem. Soc. Jpn., 61,
3283-3288 (1988); Bull. Chem. Soc. Jpn., 63, 258-259 (1990); and Chemistry
Letters, p. 1633-1636 (1988). The hydrous zirconium oxide was prepared by
reacting zirconium oxychloride (ZrOCl.sub.2) with sodium hydroxide at room
temperature and the resulting precipitate was washed free of resulting
chloride ion yielding a hydrated zirconium hydroxide-oxide.
Despite the teachings of the prior art, a need exists for a heterogeneous
catalyst for the reduction of aldehydic or ketonic compounds having high
catalytic activity which can either be easily removed from the reaction
products or more preferably, can be fixed in the reactor and regenerated
to maintain high catalytic activity.
SUMMARY OF THE INVENTION
The present invention provides a predominately tetragonal ZrO.sub.2
catalyst supported on a neutral support. As used herein, "predominately"
is understood to mean greater than 50 percent. The novel catalyst can be
advantageously employed in the reaction of an .alpha.,.beta.-olefinically
unsaturated aldehydic or ketonic compound with an alcohol to form the
corresponding allylic alcohol derivative. Since this reaction is
reversible, the catalyst is also effective in the oxidation of an allylic
alcohol to the corresponding unsaturated aldehydic or ketonic derivative.
Other catalysts found to be effective in these reactions include supported
TiO.sub.2, Nb.sub.2 O.sub.5, V.sub.2 O.sub.5, HfO.sub.2 and Ta.sub.2
O.sub.5 catalysts on a neutral support.
DETAILED DESCRIPTION OF THE INVENTION
The predominately tetragonal ZrO.sub.2 catalyst is prepared by impregnating
a neutral support to incipient wetness. Incipient wetness as used herein
is defined as the volume of solution needed to thoroughly wet the catalyst
support but not leave excess liquid present. In effect this fills the
catalyst support pores and coats the catalyst support external surface
with the liquid.
The zirconium-containing solution and support are well mixed until the
support absorbs the zirconium solution. The zirconium-containing support
is air dried and then oven dried at a temperature between about
250.degree. C. and about 350.degree. C., preferably about 300.degree. C.
for a period of from about 2 to about 4 hours, preferably for about 3
hours. The high temperature drying for the extended period of time is
necessary to volatilize or drive off anions from the surface of the
support.
The supports should have no or substantially no Lewis or Bronsted acid or
base sites. Submersion of the support into neutral water should not cause
the pH of the water to vary by more than (.sup..+-. 1) pH unit. Suitable
supports include but are not limited to silica, various carbons, germanium
oxide, and aluminas, of which silica is preferred.
The support is preferably a high surface area support, generally containing
from about 10 to about 1000 square meters/gram, preferably from about 150
to about 500 and most preferably from about 200 to about 400 square
meters/gram. The pore volume of the support typically ranges from 0.1 to
about 2.0 cubic centimeters per gram and preferably ranges from 0.5 to
about 1.5 cubic centimeters per gram.
The support can be in any desired physical shape. For example the support
can be a powder, wire, chips, or a shaped piece such as wire, strip, coil
or bead. In general the form or shape of the support depends on the design
of the reactor employed. Determining the shape or form of the support is
readily appreciated by one with ordinary skill in the art. High surface
area silica beads (5-10 mesh particles or 1/8" to 1/4" extrudates) are
readily available from suppliers such as Philadelphia Quartz Co. or W.R.
Grace & Company.
The zirconium source deposited on the silica is important in preparing the
catalyst. The zirconium-containing compound is soluble in a solvent and
must contain an anion which decomposes upon heating or an anion which is
volathe. The zirconium-containing compound must be soluble in a solvent so
that a uniform coating of the support with the zirconium-containing
compound is achieved. Illustrative of the zirconium-containing compounds
which may be employed include, but not limited to, aqueous
ZrO(NO.sub.3).sub.2, ZrOCl.sub.2, ZrCl.sub.4,
Zr(OCH(CH.sub.3).sub.2).sub.4 in isopropanol,
Zr(OCH(CH.sub.3).sub.2).sub.4 in ethanol/acetic acid solution and a
ZrO.sub.2 colloidal dispersion in water (approximately 0.01 micron
ZrO.sub.2). Especially preferred is aqueous ZrO(NO.sub.3).sub.2.
The amount of zirconium oxide deposited on the support may vary from about
0.1 to about 25.0 weight percent, preferably from about 1.0 to about 11.0
and most preferably from about 2.0 to about 8.0 weight percent.
The supported TiO.sub.2, Nb.sub.2 O.sub.5, V.sub.2 O.sub.5, HfO.sub.2 and
Ta.sub.2 O.sub.5 catalysts, here after referred to as the metal oxide
catalysts, are prepared in a similar manner to the supported ZrO.sub.2
catalyst. The support is impregnated with the metal-containing solution,
e.g. Ti, Nb, etc., to incipient wetness. The support is then allowed to
absorb the solution and is dried at room temperature. The
metal-impregnated support is then oven-dried at a time and temperature
using a procedure similar to that used in producing the supported
ZrO.sub.2 catalyst. As with the supported ZrO.sub.2 catalyst, the
metal-containing solution must contain an anion which decomposes upon
heating or an anion which is volathe in order to provide the desired metal
oxide catalyst. Suitable titanium, niobium vanadium, hafnium and
tantalum-containing solutions will be readily apparent to those with
ordinary skill in the art.
The amount of metal oxide catalyst deposited on the support may vary from
0.1 to about 25 weight percent, preferably from about 1.0 to about 11.0
and most preferably from about 2.0 to about 8.0 weight percent.
The tetragonal zirconium oxide and metal oxide supported catalyst are
advantageously employed in an improved process for converting
.alpha.,.beta.-olefinically unsaturated aldehydic or ketonic compounds to
the corresponding alcohol in the presence of a catalyst. This reaction is
commonly known to those in the art as the Meerwein-Ponndorf-Verly (MPV)
reduction. See Wilds, Org. Reactions, 2, 178 (1944). The reverse reaction
is an Oppenauer oxidation with alcohols being oxidized by ketones or
aldehydes in the presence of catalytic compound, typically aluminum
alkoxide. See Djerassi, Organic Reactions, 6,207 (1951).
The MPV/Oppenauer reactions are represented by the following reversible
equations.
R.sub.1 R.sub.2 CHOH+R.sub.3 R.sub.4 C.dbd.O.revreaction.R.sub.1 R.sub.2
C.dbd.O+R.sub.3 R.sub.4 COH
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are hydrogen or hydrocarbon
radicals containing between 1 and 18 carbon atoms. Suitable hydrocarbon
radicals include alkyl, aryl, alkyl-substituted aryl groups and the like.
R.sub.1 and R.sub.2 may be the same or different and R.sub.3 and R.sub.4
may be the same or different provided that R.sub.1, R.sub.2, R.sub.3 and
R.sub.4 are not the same.
A cyclic mechanism appears to prevail in the MPV reaction in which the
.alpha.-hydrogen of the alcohol is transferred with its pair of electrons
to the carbonyl carbon of the ketone; this results in the ketone/aldehyde
of the alcohol and an alcohol from the reagent ketone/aldehyde. This
reaction can be driven to the product side by excess of alcohol and by
distilling off a low boiling product, e.g., acetaldehyde or acetone. When
the alcohol has an .alpha.-D, e.g., (CH.sub.3).sub.2 CDOH, then the
deuterium atom transfers to the .alpha.-carbon of the reduced ketone.
##STR1##
The MPV reaction is normally carried out in homogeneous solution using
aluminum tri(isopropoxide) as catalyst and isopropanol as the preferred
reducing agent/catalyst combination. A low boiling product, such as
acetone,is distilled off as it appears in the reaction to shift the
equilibrium to the product side. The inverse procedure is conducted for
the Oppenauer oxidation, e.g., when an appropriate alcohol is oxidized
using a ketone or aldehyde as the oxidizing agent the removal of the
generated aldehyde or ketone drives the reaction to the product side.
The .alpha.,.beta.-olefinically unsaturated carbonylic compounds used in
the present process invention include those which correspond to the
formula:
##STR2##
wherein R is a substituent selected from hydrogen and hydrocarbon radicals
containing between one and 18 carbon atoms. The R substituents can be the
same or different. More preferably R is a substituent select from the
group hydrogen and alkyl groups containing 1 to 4 carbon atoms.
Illustrative of .alpha.,.beta.-olefinically unsaturated compounds which
can be selectively reduced or oxidized in accordance with the invention
process include but are not limited to acrolein, methacrolein,
crotonaldehyde, tiglic aldehyde, .alpha.-ethylacrolein, cinnamaldehyde,
hexanal, methyl vinyl ketone, methylisopropenyl ketone and alcohols such
as cinnamyl alcohol, isopropanol and the like. Halogen and nitrogen
substituents may also be selectively reduced to allylylic derivatives.
Alcohols are the hydrogen donors in the MPV reaction being oxidized to
ketone or aldehydes. Generally a secondary alcohol such as isopropanol is
preferred, however other alcohols including but not limited to 2-butanol
and ethanol may also be employed.
In the practice of the process, the .alpha.,.beta.-olefinically unsaturated
carbonylic compound and alcohol are passed through a reaction zone
containing supported ZrO.sub.2, Ta.sub.2 O.sub.5, TiO.sub.2, Nb.sub.2
O.sub.5, V.sub.2 O.sub.5 or HfO.sub.2 catalysts and mixtures thereof. The
reaction can be carried out in the liquid or gas phase.
The reaction temperature of the process can vary in the range between about
50.degree. C. and 250.degree. C. and preferably between about 150.degree.
C. and 225.degree. C. The pressure of the hydrogenation process can vary
in the range between about 15 and 1000 psia and preferably between about
200 and 550 psia, and most preferably between about 400 and 550 psia.
The mole ratio of the alcohol to .alpha.,.beta.-olefinically unsaturated
aldehydic or ketonic compound in the feed can vary in the range between
about 1:1 and 1000:1, preferably between about 2:1 and 25:1 and most
preferably between about 5:1 and 20:1.
The rate at which the alcohol and aldehydic or ketonic compound contact the
catalyst is not critical. The feed rate can be varied with other
conditions to optimize aldehyde/ketone conversion and yield of the
unsaturated alcohol. The liquid hourly space velocity (LHSV) varies at a
rate between about 0.01 and 10 hours.sup.-1 and most preferably from about
0.5 to about 4.0 hours.sup.-1.
The process can be conducted by either continuous, semi-batch or batch
methods. The feed streams can be passed through a fixed catalyst bed or
into a fluidized reactor in which the catalyst is present in finely
divided form. In a preferred method, continuous operation is maintained by
feeding the alcohol and aldehydic or ketonic compound into a reactor at
the desired temperature and pressure. The reactor is preferably comprised
of tubes containing the catalyst, although many other designs are known in
the art. After contacting the catalyst the effluent is separated from the
catalyst by conventional means, if necessary, and the products recovered.
Most commonly distillation is employed to separate the reaction products
into the desired components. Unreacted materials are advantageously
recycled to the inlet of the reactor.
In particular, the method of the present invention is especially preferred
for the conversion of acrolein to allyl alcohol using an alcohol,
preferably a secondary alcohol as the hydrogen donor. The reaction using
isopropanol as the hydrogen donor is presented below.
##STR3##
The acrolein to allyl alcohol reaction is conducted at a temperature
ranging from about 100.degree. to about 225.degree. C., preferably from
135.degree. to about 220.degree. C. and most preferably from 160.degree.
to about 200.degree. C. Reaction pressure may vary widely from 15 to 1000
psia. Preferably the reaction is conducted at a pressure such that the
reactants are in the liquid phase. The LHSV of the reactants typically is
from about 0.05 to about 12.0 hours.sup.-1 and preferably from about 0.5
to 4.0 hours.sup.-1.
The acrolein which is to be converted to allyl alcohol is preferably
substantially anhydrous. Substantially anhydrous, as used herein is
defined as the removal of water to less than 3.0 weight percent from the
acrolein. Commercial grade acrolein typically contains 2-5% by weight
water. It is desirable to use substantially anhydrous acrolein because
water adversely effects the activity of the catalyst.
Preferably acrolein is also inhibited with free radical scavenger(s) to
prevent its undesired free radical polymerization. Free radical scavengers
at levels of from about 10 to about 2000 parts per million are
advantageously employed, preferably from about 800 to about 1200 and most
preferably 1000 parts per million based on the weight of acrolein.
Hydroquinone is especially preferred although many other inhibitors known
in the art may be employed.
The aforementioned polymer formation can adversely effect catalyst
activity. It has been surprisingly discovered that catalytic activity can
be regained by heating the catalyst to a temperature exceeding 200.degree.
C., preferably exceeding 275.degree. C. in an oxygen containing
atmosphere, to regenerate the catalyst to substantially the same catalytic
activity as the catalyst originally possessed. More preferably the
catalyst is regenerated by heating the catalyst to a temperature exceeding
300.degree. C. in an oxygen-containing atmosphere. Without wishing to be
bound to a particular theory it is believed that polymer from the catalyst
oxidizes to carbon dioxide and water in the high temperature thereby
regaining surface area lost by polymer buildup on the catalyst.
Whereas the exact scope of the present invention is set forth in the
appended claims, the following specific examples illustrate certain
aspects of the present invention and, more particularly point out methods
of evaluating the same. However, the examples are set forth for
illustration only and are not to be construed as limitations on the
present invention except as set forth in the appended claims. All parts
and percentages are by weight unless otherwise specified.
DESCRIPTION OF THE REACTOR
A vertical 316 stainless steel pipe reactor with an outside diameter of
1.91 centimeters and an inside diameter of 1.4 centimeters was used in the
following Examples. The reactor was 91 centimeters in length. A 3
millimeter outside diameter thermocouple well was centered in the reactor
with ten thermocouples spaced 3.8 centimeters apart. The catalyst bed was
located between thermocouple 4 and 9 (thermocouple 1 was located on top).
The liquid reactants were fed through the bottom using a plunger pump. The
bottom 33 centimeters of the reactor was the preheat zone. The feed then
enters approximately a 9 centimeter bed of 1/8-inch glass balls, followed
by approximately 20 centimeters of the particulate catalyst, having an
approximate volume of 30 cubic centimeters, and an approximate mass of 14
grams. The catalyst bed was topped with 26 centimeters of 1/8-inch glass
balls.
The reactor was equipped with four electric heaters (600 watts), each
independently controlled on the outside of the 1.91 centimeter outside
diameter purge.
A pressure sensor and controller activates a pneumatic valve which was on
the cold side of a small heat exchanger.
Analytical samples (1-2 milliliter) were removed from the product stream
and analyzed.
ANALYTICAL PROCEDURE
The samples were analyzed using a Hewlett Packard 5890-A gas chromatograph
(flame ionizing detector, helium carrier gas at 40 pounds per square inch)
and a 30 meter capillary column coated with Supelco Wax-10.RTM.
(Carbowax.RTM.). The sample to be analyzed (approximately 0.05 microliter)
was injected into the 300.degree. C. injection port with the column held
at 40.degree. C. for 5 minutes. The sample temperature is then ramped at
10.degree. C. per minute until reaching 200.degree. C. The column was then
held at 200.degree. C. for approximately 10 minutes.
CATALYST PREPARATION
A bead-type silica with a particle size of 5-10 mesh known as Cariact-10
(available from Davison Chemical Division, W.R. Grace & Co.) was used as
the support. The silic a was an amorphous silica with a surface area of
300 square meters/gram and a pore volume of 1.02 cubic centimeter/gram.
The silica had a uniform pore diameter of approximately 100 Angstroms.
Twenty-five grams of the silica beads were contacted with a solution of
2.54 grams of ZrO(NO.sub.3).sub.2 (equivalent to 1 gram Zr, obtained from
Alfa Chemical Co.) dissolved in approximately 40 milliliters of distilled
water. The solution was completely imbibed by the catalyst beads. The
silica and zicronium-containing solution were well mixed until all the
beads were clear.
The beads were then allowed to dry (approximately 18 hours) in air at
ambient temperature. Dry beads have a slightly hazy appearance. The beads
were then heated in air in a 300.degree. C. muffle furnace for three
hours. The heated beads weighed 26.3 grams and contained approximately 4
percent by weight ZrO.sub.2.
Surface science study of the approximately 4 weight percent ZrO.sub.2 on
SiO.sub.2 was conducted using powder X-ray diffraction (PXRD), secondary
ion mass spectroscopy (SIMS), scanning electron microscopy (SEM) and X-ray
photoelectron spectroscopy (XPS). The XPS in particular, showed that the
ZrO.sub.2 particles on the SiO.sub.2 support were substantially all in the
tetragonal crystal form and not in the monoclinic form.
OPERATION OF THE REACTOR
At atmospheric pressure and ambient temperature the reactor was pressured
with anhydrous alcohol. The reactor was then brought to temperature and
switched to the acrolein feed. After about two hours, steady state
conditions were achieved and the product composition was constant. The
feed was pumped into the reactor at a rate of 50-150 milliliters/hour
which is a liquid hour space velocity of approximately 1.6 to 5.0 for the
30 cubic centimeter catalyst bed volume.
The gross liquid product was cooled by use of a water-cooled heat exchanger
and discharged into a 5 percent by weight aqueous Na.sub.2 CO.sub.3
solution (to neutralize any unreacted acrolein). One milliliter samples of
the unquenched product was put into serum stoppered bottles and analyzed
by the gas chromotography methods discussed above.
EXAMPLE 1
Various sources of Zr.sup.+4 on silica support were evaluated as catalysts
for the conversion of acrolein to allyl alcohol. The supplier of the
zirconium salts and its form is reported below. The method of preparation
is also provided. The silica employed was Fuji-Davison Cariact-10, 5-10
mesh beads (W.R. Grace & Co.). After the zirconium source was applied to
the silica, the beads were dried at 300.degree. C. in air to convert the
zironium to its oxide.
After the catalysts were prepared their effectiveness was evaluated using a
7.2 weight percent acrolein 92.8% isopropanol feed, with a LHSV of
approximately 3 at 175.degree. C. and 500 psia.
The results are presented below.
__________________________________________________________________________
J-M.sup.b
Zr.sup.+4 Supplier
J-M.sup.b
J-M.sup.b
Aldrich.sup.c
Aldrich.sup.c
Aldrich.sup.c
Aldrich.sup.c
20% Aldrich.sup.d
Zr.sup.+4 Source
ZrO(NO.sub.3).sub.2.sup.a
ZrO(NO.sub.3).sub.2.sup.a
ZrO(NO.sub.3).sub.2.sup.a
ZrCl.sub.4
Zr(Oipr).sub.4
Zr(OEt).sub.4
ZrO.sub.2 (Sol)
ZrO(NO.sub.3).sub
.2
Ethanol
Iospropanol
Soln. +3% Aqueous
Aqueous Soln. Soln. to
Acetic Acid, Soln. to
to Incipient Incipient
washed with
Dilute
Incipient
Wetness Wetness
Hexane, Dried
with
Wetness O
Method Dried in Air Dried in Air
in Air Air Dried
Air
__________________________________________________________________________
Dried
Catalytic Activity
Acrolein Conv. (%)
99 99 99 99 97 96 99 98.sup.d
94.sup.d
96.sup.d
Efficiency to Allyl.sup.e
90 90 95 90 84 89 88 87
90
85
Alcohol (%)
__________________________________________________________________________
.sup.a Different batches of
.sup.b JM is Johnson Matthey Company Inc.
.sup.c Aldrich is Aldrich Chemical Company, Inc.
.sup.d Triplicate preparation and evaluation
.sup.eEfficiency to Allyl Alcohol is defined herein as the mole percent
acrolein converted to allyl alcohol.
The above results demonstrate the efficiency of the ZrO.sub.2 silica
supported catalyst in the reaction of acrolein to allyl alcohol prepared
by various methods and four different sources of Zr.sup.+4 sources.
EXAMPLE 2
______________________________________
Effect of ZrO.sub.2 Concentration on Support
On Catalyst Activity
A B C D E F.sup.1
______________________________________
Weight % ZrO.sub.2
0.0 0.5 5.4 11.8 100 5.4
Acrolein Conversion
8 97 98 99 43 99
Efficiency to Alkyl
0.0 90 87 88 47 88
Alcohol
ESCA Results.sup.2
Zr on outside 0.0 0.6 1.9 5.8 100 22.6
Surface of Pellet
(mole %)
Zr on inside Surface
0.0 0.1 1.4 0.9 100 1.4
of Pellet
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.sup.1 Dispersion of ZrO.sub.2 solution in water (0.01 micron size
ZrO.sub.2 dispersion)
.sup.2 ESCA electron scattering for chemical analysis
The above Example demonstrates several results. The neat or 100% ZrO.sub.2
catalyst (Example E) was not as effective as the ZrO.sub.2 on SiO.sub.2
support catalysts (Examples B, C, and D) as the acrolein conversion and
allyl alcohol efficiency indicate.
Example A demonstrates that the SiO.sub.2 support is not active.
Examples B, C, and D demonstrate that the ZrO.sub.2 concentration on the
support was not critical.
Finally Example F demonstrates that uniform distribution of the ZrO.sub.2
on or within the support particle is not needed.
EXAMPLE 3
A long-term study of the conversion of acrolein to allyl alcohol was
conducted using approximately 4% ZrO.sub.2 (from zirconium oxynitrate) on
SiO.sub.2 (Fuji-Davison Cariact-10). A LHSV of approximately 3, using a
12:1 molar isopropanol acrolein feed ration to the reactor at 500 psi was
employed.
After 215 hours on stream the catalyst was treated with oxygen containing
gas at atmospheric pressure, at a temperature of approximately 300.degree.
C. for approximately four or five hours. The following results were
obtained.
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Time (hours on
5 158 160 215 238 283 287
stream)
Temperature (.degree.C.)
175 175 200 175 175 175 200
Acrolein Con-
98.4 90.3 94.6 85.2 86.7 88.3 96.0
version (weight %)
Efficiency to Allyl
77.1 79.8 77.3 79.5 61.9 68.9 73.3
Alcohol (mole %)
Product Analysis (gas chromatography area percent)
Acrolein 0.11 0.70 0.39 1.07 0.96 0.84 0.29
Acetone 6.25 5.82 6.15 5.57 5.28 5.41 6.25
Allyl Alcohol
5.66 5.37 5.67 5.05 4.00 4.54 5.25
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The above results demonstrate that the ZrO.sub.2 /SiO.sub.2 catalyst can be
regenerated by heating the catalyst in an oxygen-containing atmosphere.
Furthermore, when the reaction temperature was raised from 175.degree. C.
to 200.degree. C. the acrolein level decreased (0.39 and 0.29) versus the
acrolein level at 175.degree. C. (0.70, 1.07, 0.96 and 0.84).
EXAMPLE 4
The catalytic activity of various metal oxides on silica support was
evaluated by converting acrolein to allyl alcohol. Aqueous metal nitrate
solutions were used to impregnate Cariact-10, 5-10 mesh silica to
incipient wetness. The silica was then air dried and them oven heated at
300.degree. C. or 425.degree. C. for 3 hours in air. The catalyst was then
placed in the reactor and a 7.1% acrolein in isopropanol feed, having a
LHSV of approximately 3.3 was feed through the catalyst at 175.degree. C.
and 500 psi. The acrolein conversion and allyl alcohol efficiency are
presented below for the various catalysts.
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Metal
TiO.sub.2
ZrO.sub.2
HfO.sub.2
V.sub.2 O.sub.5
Nb.sub.2 O.sub.5
Ta.sub.2 O.sub.5
Al.sub.2 O.sub.3.sup.1
In.sub.2 O.sub.3
ZnO
Sc.sub.2 O.sub.3
Y.sub.2 O.sub.3.sup.1
La.sub.2 O.sub.3.sup.1
Nd.sub.2 O.sub.3.sup.1
Gd.sub.2 O.sub.3.sup
.1 CeO.sub.2
Oxide/
on SiO.sub.2
Acrolein
55 98 100
34 72 98 .about.54
20 49 70 47 27 .about.64
.about.59
19
Con-
version
(weight
%)
Effi-
55 87 88 58 56 80 0 0 19 35 19 0 .about.18
.about.15
29
ciency to
Allyl
Alcohol
(mole %)
__________________________________________________________________________
.sup.1 Dried at 425.degree. C. in air for 3 hours
The above results demonstrate the efficiency of the ZrO.sub.2, HfO.sub.2,
Ta.sub.2 O.sub.5 TiO.sub.2, NbO.sub.5 and V.sub.2 O.sub.5 catalysts in
converting acrolein to allyl alcohol.
EXAMPLE 5
A ZrO.sub.2 was prepared by mixing Degussa zirconium dioxide (Degussa
Corp., Pigment Division, having a surface area of approximately 40 square
meters/gram, 300 Angstrom average particle size with greater than 97% of
the ZrO.sub.2 having a monoclinic crystal form) with Ludox 40 (Dupont a
colloidal SiO.sub.2 --NH.sub.4 + counterion) dried in air and heated to
450.degree. C. for 20 minutes. The resulting catalyst had a surface area
of 40 square meters/gram and approximately 300 Angstrom particle size. The
resulting catalyst was found to contain approximately 44% ZrO.sub.2 and
56% SiO.sub.2.
The catalyst was then placed into service in the reactor using the
conditions described in Example 4. The acrolein conversion was 23% and the
efficiency to allyl alcohol was 36%. The diminished catalytic activity is
believed to be caused by the low surface area of the fumed silica support
and the ZrO.sub.2 being predominately in the monoclinic crystalline form.
EXAMPLE 6
In order to evaluate the effect the silica support had an efficiency of the
catalyst, two similar silica products were evaluated. One silica was
obtained from Fuji-Davison Division of W.R. Grace & Co. (Cariact-10) and
the second silica from Philadelphia Quartz (PQ).
The silicas were than used as supports for the ZrO.sub.2 catalyst using
similar preparation methods. The catalyst were then evaluated by placing
the catalysts into service at 175.degree. C., at 500 psia, LHSV of
approximately 3, using a 12:1 isopropanol: acrolein molar feed ratio and
evaluating the efficiency to allyl alcohol. The following results were
obtained.
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Cariact-10 PQ
______________________________________
size 5-10 mesh 1/16 inch extrudate
surface area approximately 200
approximately 210
(square meter/gram)
Pore size (Angstroms)
approximately 100
approximately 110
Acrolein Conversion
99 96
(weight percent)
Efficiency to 90 88
Allyl Alcohol
(mole %)
______________________________________
The above results demonstrate the efficiency of various silica support
sources in the present invention.
COMPARATIVE EXAMPLE
A "hydrous" ZrO.sub.2 catalyst was prepared using the following procedure.
ZrO.sub.2 was precipitated using sodium hydroxide from an aqueous
ZrOCl.sub.2.8H.sub.2 O solution. The precipitate was washed, dried, and
heated at 400.degree. C. for 18 hours. This 100% unsupported hydrous
ZrO.sub.2 catalyst was then evaluated using reaction condition described
in Example 6.
The hydrous ZrO.sub.2 catalyst yielded an acrolein conversion of 36 weight
percent and an efficiency to allyl alcohol of 17 mole percent.
The above results demonstrate that the hydrous ZrO.sub.2 material disclosed
in the prior art is an inferior catalyst to the predominately tetragonal
ZrO.sub.2 and metal oxide supported catalysts of the present invention.
EXAMPLE 7
An alumina oxide obtained from United Catalysts Inc., was employed as a
support for the ZrO.sub.2 catalyst using preparation and reaction
conditions specified in Example 6. The 1/8" extrudate was a neutral
gamma-alumina oxide derived from a neutral alkoxide.
The ZrO.sub.2 on Al.sub.2).sub.3 catalyst produced an acrolein conversion
of 59 weight percent an allyl alcohol efficiency of 57 mole percent.
EXAMPLE 8
A 94% sec-butanol/5.9% acrolein stream containing 0.12% hydroquinone was
fed to the reactor at 175.degree. C., and 500 psia., with a LHSV of
approximately 3. An approximately 4% weight ZrO.sub.2 /SiO.sub.2 supported
catalyst was employed.
The conversion of acrolein to allyl alcohol using sec-butanol was similar
to the conversion which resulted when isopropanol was employed as the
hydrogen donor.
EXAMPLE 9
An approximately 4 weight percent ZrO.sub.2 /supported SiO.sub.2 catalyst
was evaluated in the reduction of acetyl norbornene to
2-(sec-hydroxyethyl)-5-norbornene. Isopropanol was employed as the
hydrogen donor at 12:1 alcohol-ketone ratio, with a LHSV of approximately
3 at a temperature from 100.degree.-225.degree. C.
The catalyst provided an 80% conversion of the ketone to the alcohol.
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